The synergistic effect of high K+ and hypoxia on extracellular concentrations of neuroactive amino acid in hippocampus

In the present study, we examined extracellular concentrations of glutamate (Glu) in hypoxia using ringer solution with a high potassium (K+) level using microdialysis. Based on our findings, we hypothesized that the concentration of extracellular K+ caused a greater efflux of Glu. We used male SD rats and separated them into 3 groups based on the K+ concentration of Ringer solution (RS), consisting of normal (4 mM), 40 mM and 150 mM groups. We stereotactically inserted the microdialysis probe into the hippocampus, and perfused the RS for 60 min before imposing hypoxia. Subsequently, while perfusing RS, hypoxia (7% O2 + 93% N2 gas) was induced in all 3 groups for 20 min. In the normal and 40 mM of K+ concentration groups, the Glu level did not increase, but in the 150 mM of K+ concentration group, the Glu level increased while being perfused with RS and a larger increase in Glu was observed after inducing hypoxia. This result suggests that the extracellular concentration of K+ plays a role in the mechanism of increased neuronal vulnerability caused by hypoxia after TBI.

Mn-SOD and Bcl-2 expression after repeated hyperbaric oxygenation

To clarify the mechanism of ischemic tolerance induced by HBO, we investigated the effect of HBO on immunoreactivity to Bcl-2 and Bax, apoptosis-regulating protein, or Mn-SOD, a radical scavenging system, in the CA1 sector of the gerbil hippocampus. Pretreatment comprising, five sessions at 2 ATA (atmosphere absolute) every other day, but not that comprising, ten sessions at 3 ATA every day, caused significant increases in Bcl-2 and Mn-SOD immunoreactivity in the CA1 sector compared with in the sham pretreatment group. No significant differences in Bax immunoreactivity and neuronal density in the CA1 hippocampal neurons was observed between the groups. These results suggest that protection against mitochondrial alterations after ischemia through Mn-SOD and/or Bcl-2 expression is related to the ischemic tolerance induced by repeated HBO pre-treatment.

Hepatocyte growth factor reduces infarct volume after transient focal cerebral ischemia in rats

Hepatocyte growth factor (HGF) was originally discovered as a powerful mitogen for hepatocytes. HGF functions both as a neurotrophic factor as well as an angiogenetic factor. Furthermore, HGF has an anti-apoptotic effect on vascular endothelial cells. The present study examined the neuroprotective effect of HGF after transient focal cerebral ischemia in rats, in which an anti-apoptotic and an angiogenetic effect of HGF was assumed to contribute to the reduction of the infarct volume. The intraventricular administration of human recombinant HGF (90 micrograms) significantly reduced the infarct volume after 120 minutes occlusion of both the right middle cerebral artery (MCA) and the bilateral common carotid arteries (CCAs). In a separate series of experiments, we investigated both the anti-apoptotic effect on neurons and the angiogenetic effect of HGF histopathologically. The number of survival neurons and vascular lumina in the HGF group were significantly higher than those in the vehicle group. A large number of TUNEL positive neurons were observed in the inner boundary of the infarct area in the vehicle group, whereas only a few TUNEL positive neurons were observed in a corresponding area in the HGF group. In the HGF group, Bcl-2 protein was obviously represented in survival neurons as well as in vascular endothelial cells and in glial cells subjected to ischemia. These data suggest that HGF prevents apoptotic neuronal cell death by upregulating the production of Bcl-2 protein and by an angiogenetic effect in the central nervous system which affected transient focal cerebral ischemia.

Preferential conditions for and possible mechanisms of induction of ischemic tolerance by repeated hyperbaric oxygenation in gerbil hippocampus

OBJECTIVE

We reported previously that repeated hyperbaric oxygenation (HBO) as pretreatment induced ischemic tolerance in the gerbil hippocampus. This study was conducted to determine the preferential conditions for induction of ischemic tolerance by HBO and the mechanism of this induction through immunohistochemical analysis of Bcl-2, Bax, and manganese superoxide dismutase expression.

METHODS

Five-minute forebrain ischemia was produced in gerbils after pretreatment with 2 atmospheres absolute (ATA) HBO once every other day for one, three, or five sessions, 2 ATA hyperbaric air once every other day for five sessions, or 3 ATA HBO once daily for 10 sessions. Histological examinations were then performed. Two days after pretreatment with 2 ATA HBO once every other day for five sessions or with 3 ATA HBO once daily for 10 sessions, sections were analyzed immunohistochemically.

RESULTS

Pretreatment with 2 ATA HBO once every other day for three or five sessions induced ischemic tolerance; however, pretreatment with 2 ATA HBO for one session, 2 ATA hyperbaric air once every other day for five sessions, or 3 ATA HBO once daily for 10 sessions did not. Pretreatment with 2 ATA HBO once every other day for five sessions, but not with 3 ATA HBO once daily for 10 sessions, significantly increased Bcl-2 and manganese superoxide dismutase immunoreactivity in the CA1 sector.

CONCLUSION

These results suggest that protection against mitochondrial alterations after ischemia through manganese superoxide dismutase and/or Bcl-2 expression may be related to induction of ischemic tolerance by repeated HBO pretreatment.

Inhibition of experimental vasospasm by pretreatment with ultraviolet light irradiation in a rat femoral artery model

OBJECTIVE

Chronic cerebral vasospasm is resistant to conventional treatments despite recent advances in treatment modalities. We studied the preventive effect of ultraviolet (UV) irradiation on development of vasospasm and its mechanism in a rat femoral artery model.

METHODS

The rat femoral artery model for vasospasm was used in this investigation (n = 108). The femoral arteries were divided into four groups: empty and no irradiation (control), UV irradiation (UV group), blood placement (VS group), and blood placement after UV irradiation (VS + UV group). Luminal area was measured, and smooth muscle cell counts in the medial layer of the vessel wall were obtained. An immunohistochemical study was performed with cross sections of fixed femoral arteries at 12 hours and 1, 3, 5, 7, and 49 days after blood placement. The rings of femoral arteries on Day 7 were subjected to pharmacological study.

RESULTS

Pretreatment with UV irradiation (VS + UV group) resulted not only in significant inhibition of chronic vasospasm but also in a significant decrease in smooth muscle cells compared with the VS group on Days 5 and 7. The UV-treated arteries (UV and VS + UV groups) exhibited a significant number of Bax- and Bcl-2-positive cells on Days 5 and 7, but few CPP-32 positive cells were observed at the same time points. In the pharmacological study, contractile response to KCI or phenylephrine was reduced significantly in the UV-treated arteries.

CONCLUSION

These results imply that UV irradiation prevents chronic vasospasm and suggest that UV-induced cell death plays an important role in the preventive effect without causing complications during the chronic period.

High-Q concentrated directional emission from egg-shaped asymmetric resonant cavities

We propose the use of egg-shaped asymmetric resonant cavities (ARCs), each of which consists of a half-circular part and a half-deformed part, as promising candidates in obtaining desirable whispering-gallery-mode resonances. According to numerical analysis based on a ray-optics model, more than an order-of-magnitude higher Q and more-concentrated emission from the tip of the egg region were obtained for egg-shaped ARCs than for the previously studied quadrupolar ARCs.

Evaluation of spontaneous intracranial hypotension: assessment on ICP monitoring and radiological imaging

We describe two recent cases of spontaneous intracranial hypotension. A 38-year-old woman developed a severe postural headache. Magnetic resonance imaging (MRI) showed marked dural enhancement. Histopathological findings of dural biopsy showed numerous dilated vessels in the dura, rather than hypertrophic change. Lumber CSF pressure was 5 cmH2O and RI cisternography suggested CSF leakage. A 58-year-old woman with postural headache and vertigo had bilateral subdural haematoma associated with diffuse dural enhancement on MRI. Lumber CSF monitoring confirmed persistent low pressure ranging from 0-5 cm H2O. MRI myelography revealed multiple CSF pouches along the whole spinal axis. CSF leakage was demonstrated on Radioisotope (RI) cisternography. Both cases described in this report were diagnosed as spontaneous intracranial hypotension caused by CSF leakage from spinal meningeal diverticula and were successfully treated by intravenous Factor XIII administration.

[Prediction of the need for mechanical ventilation after transsternal thymectomy in patients with myasthenia gravis]

Between June 1992 and May 2000, transsternal extended thymectomy was performed for 70 patients with myasthenia gravis in our hospital. We were able to evaluate 64 of them in terms of prediction of the need for postoperative mechanical ventilation using the score systems reported by Leventhal et al., Kimura et al. and the criteria of Adachi et al.. For these systems, the rates of agreement between predictions and results were 85.9%, 82.8%, and 64.1%, respectively. The two former systems had some false negative cases (i.e., they predicted that ventilation would not be needed when in fact it was), but the last one gave no false negatives. We recommend Adachi's criteria for clinical safety. In our cases the patients whose value of %VC multiplied by FEV1.0% was less than 7,000 (Adachi's criterion is less in 8,300), especially, needed careful management with regard to respiratory crisis.

Hepatocyte growth factor reduces the infarct volume after transient focal cerebral ischemia in rats

Hepatocyte growth factor (HGF) was originally discovered as a powerful mitogen for hepatocytes. HGF also has been reported to function as a neurotrophic factor as well as an angiogenetic factor. The present study examined the neuroprotective effect of HGF against transient focal cerebral ischemia in rats, in which an anti-apoptotic and an angiogenetic effect of HGF was assumed to contribute to the reduction of the infarct volume. The intraventricular administration of human recombinant HGF prevented neuronal death after 120 min of occlusion in the right middle cerebral artery and the bilateral common carotid arteries. HGF significantly reduced the infarct volume in a dose-dependent manner. In a separate series of experiments, we next histopathologically investigated both the anti-apoptotic effect on neurons and the angiogenetic effect of HGF. A large number of TUNEL positive neurons were observed in the inner boundary of the infarct area in both the control and the vehicle group whereas only a few TUNEL positive neurons were observed in the corresponding area in the HGF group. In the HGF group, Bcl-2 protein was obviously represented in surviving neurons subjected to ischemia. The number of the vascular lamina in HGF group were significantly higher than those in the vehicle group. These data suggest that HGF appears to have an ability to prevent apoptotic neuronal cell death while also possessing an angiogenetic effect in the central nervous system which was affected with transient focal cerebral ischemia.

Effect of leptin on insulin sensitivity in the Otsuka Long-Evans Tokushima Fatty rat

Leptin has been proposed to be a sensor of energy storage in adipose tissues, and is capable of mediating a feedback signal to the hypothalamus, which is involved in the regulation of energy homeostasis and body weight. In order to investigate the issue of whether resistance to the activity of leptin on insulin sensitivity is observed in young Otsuka Long-Evans Tokushima Fatty (OLETF) rats at 8 weeks of age, leptin (50 nmol/kg/h) was administered intravenously for 16 h to OLETF and Long-Evans Tokushima Otsuka (LETO) (lean controls) rats, followed by a measurement of insulin-stimulated glucose uptake in hindlimb muscles during hyperinsulinemic euglycemic clamp technique. In the case of LETO rats, the administration of leptin significantly decreased plasma insulin levels prior to the clamp test, but did not change plasma glucose levels. Furthermore, leptin led to an increase in insulin-stimulated glucose uptake in hindlimb muscles. However, in the case of OLETF rats, leptin administration changed neither plasma insulin levels nor insulin-stimulated glucose uptake. These data demonstrate that OLETF rats at 8 weeks of age have already become resistant to high concentration of peripheral leptin.

Early experiences of haemostasis on brain tumour surgery with Argon Plasma Coagulation (APC)

OBJECTIVE

We first applied a novel haemostatic strategy involving Argon Plasma Coagulation (APC), an innovative no-touch electrocoagulation technique in which a high-frequency alternating current is delivered to the tissue through ionized argon gas, to brain tumour surgery, and report its usefulness and limitations.

METHODS

The APC system we used comprised an APC 300 developed by ERBE Elektromedizin GmbH, Germany. We applied APC to 13 brain tumours in 12 patients (5 meningiomas, 4 sarcomas, 2 glioblastomas, and 2 pituitary adenomas). To avoid unnecessary thermal injury to the tissue as much as possible, power/gas flow settings of 20 and 40 W were used. The impact time was varied individually but was around several seconds per one impact. The argon jet (1.5-4.5 L/min) clears a field of pooled blood and evenly conducts electrical energy to the target tissue. A thin and flexible probe particularly increased the usefulness of APC for haemostasis on deep-seated skull base tumour operations under a microscope.

CONCLUSION

All patients were successfully treated and satisfied with the surgical results without any complications due to APC. APC appears to be an excellent alternative strategy for achieving haemostasis on vascular-rich brain tumour surgery, and may be valuable for the management of patients with coagulation defects.

Expression of p53 tumor suppressor gene in adenoid cystic and mucoepidermoid carcinomas of the salivary glands

Seventeen adenoid cystic carcinomas (ACCs) and 27 mucoepidermoid carcinomas (MECs) occurring in the salivary glands were analyzed for p53 tumor suppressor gene alteration (exons 5-8) and protein expression. The cell proliferation activity was also examined by Ki-67 immunohistochemistry. The p53 alterations were detected in three samples (17.6%) of ACC and in four samples (14.8%) of MEC, and were only found in carcinomas arising in the minor salivary glands. The occurrence of the p53 gene alteration is less frequent in ACC and MEC than that in other kinds of tumors, and therefore does not seem to play a critical role in the course of the tumorigenesis in ACC and MEC. All ACC samples arising from the minor salivary glands exhibiting p53 gene alterations showed recurrence/metastasis, thus suggesting a poor outcome of these patients. All ACCs and three out of four MECs samples with p53 gene alterations showed the lowest degree of p53 immunostaining ratio, thus suggesting that no correlation exists between the p53 gene alterations and the p53 immunostaining in these salivary gland carcinomas. No significant relationship was demonstrated between the immunostaining ratio of either p53 or Ki-67 and the morphological growth pattern or patient clinical course in the ACC samples. The p53 immunopositivity in MEC correlated to the histological grade. The Ki-67 immunostaining ratio was also significantly related to the histological grade and the clinical course in MEC.

[Influence of intubation maneuver with or without premedication for intracranial hemorrhage with unconsciousness]

PURPOSE

To clarify the influence of intubation maneuver with or without premedication for intracranial hemorrhage with unconsciousness.

METHODS

Between May 1995 and May 2000, we analyzed retrospectively 46 patients who had received intubation for unconsciousness and were found non-traumatic intracranial hemorrhage by head computer tomography at the Trauma and Critical Care Center, National Defense Medical College. They were divided into two groups, Drug group in which drugs were used before intubation and Control group which were intubated without drugs. Physical findings on admission, head CT findings, Glasgow Outcome Score(GOS) at discharge were analyzed between the groups.

RESULTS

There were no significant differences for background of subjects between the groups. In the Drug group, diazepam, pentazocine, lidocaine, nifedipine and nicardipine were used before intubation. GOS in the Control group was significantly greater than in the Drug group(p < 0.01).

CONCLUSION

In case of intubation for unconscious patients who may suffer intracranial hemorrhage, using premedication leads to favorable outcome.

Gene expression of angiogenesis related factors in glioma

Angiogenesis plays an important role in growth and proliferation of cancer. Various angiogenic and angiostatic factors regulate angiogenesis. In this study, we examined gene expression of the angiopoietin family including angiopoietin 1 (Ang1) and angiopoietin 2 (Ang2) in 39 gliomas and 5 glioma-xenografts by RT-PCR. Ang1 and Ang2 genes were expressed in 54%, and 77% of gliomas, respectively. The expression of Ang1 was significantly correlated with the expression of Ang2. Both Ang1 and Ang2 were shown to be expressed in the glioma cells. Ang2 gene expression was correlated with VEGF gene expression. Angiopoietin molecules may synergistically cooperate in growth and vascularization in glioma.

Influence of the presence of OB-Re on leptin radioimmunoassay

Leptin, a hormone derived from adipose tissue, regulates energy homeostasis and body weight. In the mouse, serum leptin levels, when measured by radioimmunoassay (RIA), increase by a factor of more than 50 times during pregnancy, compared with those in the non-pregnant state. It is well known that mouse placenta produces the secretory isoform of the leptin receptor, OB-Re. In order to investigate the issue of whether serum leptin levels are actually increased during pregnancy or whether the increased OB-Re concentration plays a role in this phenomenon, serum leptin levels were determined by the immunoprecipitation of leptin using anti-leptin antibody, and were found to be increased only by about ten times during pregnancy. To investigate the influence of OB-Re on leptin measurement by the RIA procedure, serum leptin levels were measured by the RIA after the addition of OB-Re to the serum. The apparent values of leptin levels increased in parallel with the amount of OB-Re added to the serum. Leptin levels, as determined by the RIA, might therefore provide artificially high values when serum levels of the secretory form of OB-R are high, in cases, for example, such as the last period of pregnancy in mice.

[Tiny aneurysms of cortical arteries presenting as an acute subdural hematoma: a case report]

A case of an acute subdural hematoma due to the rupture of a tiny aneurysm of a cortical artery is described. A 68-year-old man lightly hit the right side of his head. About 1 hour later, he became drowsy and exhibited moderate hemiparesis on the left side on admission. Computed tomographic scanning demonstrated an acute subdural hematoma on the right temporoparietal region. In the past, he had undergone the clipping of a non-ruptured aneurysm and a subdural-peritoneal shunt operation on the same side in another hospital. On surgical evacuation of the subdural hematoma, a pulsating bleeding from a ruptured tiny aneurysm of a cortical artery was observed. There were also some similar tiny aneurysms on other cortical arteries. A photograph of such a tiny aneurysm was first taken and presented.

Relationship between stroke and asymptomatic minute hemorrhages in hypertensive patients

Asymptomatic small hemorrhages were identified in hypertensive patients by T2*-weighted gradient echo magnetic resonance (MR) imaging to investigate the relationship between hypertensive intracerebral hemorrhage and asymptomatic minute hemorrhages. Forty-eight patients with hypertensive intracerebral hemorrhage or cerebral infarction with hypertension (these diseases were defined as stroke) were treated in National Defense Medical College from April 1998 to February 2000. All patients had no past history of stroke or head injury, underwent MR imaging within 6 months of the stroke attack, were aged from 40 to 80 years, and had no diagnosis of aneurysm, angioma, or moyamoya disease. Patients were divided into the infarction group and hemorrhage group. All foci over 2 mm in size appearing as hypointense on T2*-weighted MR imaging and unrelated to stroke areas were defined as minute hemorrhages. There were no significant differences between the two groups with respect to sex, age, and history of diabetes mellitus. The incidence of minute hemorrhages in the hemorrhage group (21/26) was greater than in the infarction group (9/22, p < 0.01). The incidence of minute hemorrhages in the basal ganglia (18/26) was greater in the hemorrhage group than in the infarction group (4/22, p < 0.001). Symptomatic intracerebral hemorrhage may be preceded by asymptomatic minute hemorrhage.

Spatial distribution of cingulate cells projecting to the primary, supplementary, and pre-supplementary motor areas: a retrograde multiple labeling study in the macaque monkey

We examined the location and spatial distribution of cingulate cortical cells projecting to the forelimb areas of the primary motor cortex (MI), supplementary motor area (SMA), and pre-supplementary motor area (pre-SMA) using a multiple retrograde labeling technique in the monkeys (Macaca fuscata). The forelimb areas of the MI, SMA and pre-SMA were physiologically identified, based on the findings of intracortical microstimulation (ICMS) and single cell recording. Three different tracers, diamidino yellow (DY), fast blue (FB), and wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP), were injected into each of the three motor areas in the same monkey. Retrogradely labeled cells in the cingulate cortex were plotted with an automated plotting system. Cells projecting to the forelimb area of the MI were distributed in the two separate regions situated rostrocaudally in the dorsal and ventral banks of the cingulate sulcus, namely the rostral cingulate motor area (CMAr) and caudal cingulate motor area (CMAc). These two regions corresponded to the forelimb areas identified by the ICMS in the same animal. The distribution of projection cells to the SMA overlapped extensively with that of projection cells to the MI. Although the MI received relatively sparse inputs from the CMAr than from the CMAc, the SMA received inputs from the CMAr and its adjacent areas as much as from the CMAc. The projection cells to the pre-SMA were distributed in the anterior portion of the cingulate cortex, including the anterior part of the CMAr and in a small part of the cingulate gyrus. These findings indicate that the MI and SMA share a considerable common information from the cingulate cortex, including the CMAr and CMAc, whereas the pre-SMA receives a different set of information from the anterior part of the cingulate cortex.

Genetic evidence for obesity loci involved in the regulation of body fat distribution in obese type 2 diabetes rat, OLETF

The Otsuka Long-Evans Tokushima Fatty (OLETF) rat is an animal model for obese type 2 diabetes in human. Obesity is essential for the onset of type 2 diabetes in this rat. Our present investigation was designed to identify quantitative trait loci (QTLs) contributing to obesity by performing a whole-genome search using 214 F(2) intercross progeny between OLETF and F344 rats. We have identified six QTLs responsible for adiposity indices of fat pads on rat chromosomes 2 (Obs1 for mesenteric fat), 4 (Obs2 for retroperitoneal fat), 8 (Obs3 for mesenteric fat), 9 (Obs4 for retroperitoneal fat), and 14 (Obs5 and Obs6 for retroperitoneal fat), demonstrating that the adiposity indices of individual fat pads were under the control of different genes. As expected, the OLETF allele corresponds to increased adiposity indices for all QTLs, except for Obs3, in which the F344 allele leads to an increase in the index.

Cystic schwannoma of the orbit: case report

BACKGROUND

Cystic lesions of the orbit have diverse clinical findings and histopathological features. We report an orbital schwannoma composed of a single cyst.

CASE DESCRIPTION

A 62-year-old woman with an intraconal cystic tumor in the left orbital cavity is described. The cystic tumor was totally removed and the pathological diagnosis of the cyst wall was schwannoma composed of both Antoni type A and B.

CONCLUSIONS

A rare case of cystic schwannoma of the orbit is reported. This case may contribute to an improved preoperative differential diagnosis for cystic lesions of the orbit.

Incidence of human papillomavirus 16 and 18 infection and p53 mutation in patients with oral squamous cell carcinoma in Japan

The purpose of this study was to investigate the prevalence of human papillomaviruses (HPVs) 16 and 18 infection, and p53 mutation in oral squamous cell carcinomas (SCCs) in Japanese patients. Our results showed a higher incidence of HPV16 and 18 infections than previous studies because we combined the findings of a consensus polymerase chain reaction (PCR), restriction fragment length polymorphism by using the restriction enzyme digestion of the PCR products and Southern blot hybridization. Each HPV16 and 18 E6/E7 DNA was detected in 9 (20%) and 25 (54%) of 46 samples. The p53 mutation in the exons from 5 to 8 were detected in 20 out of 46 samples (43%) by a PCR-single strand conformation polymorphism analysis. There was a significant relationship between HPV16 and the p53 mutation (P =0.02) suggesting that HPV16 infection has a mutagenic effect in oral SCC. However, neither HPV infection nor p53 mutation influenced survival.

Neuronal activity in the supplementary and presupplementary motor areas for temporal organization of multiple movements

To study how neurons in the medial motor areas participate in performing sequential multiple movements that are individually separated in time, we analyzed neuronal activity in the supplementary (SMA) and presupplementary (pre-SMA) motor areas. Monkeys were trained to perform three different movements separated by waiting times, in four or six different orders. Initially each series of movements was learned during five trials guided by visual signals that indicated the correct movements. The monkeys subsequently executed the three movements in the memorized order without the visual signals. Three types of neuronal activity were of particular interest; these appeared to be crucially involved in sequencing the multiple motor tasks in different orders. First, we found activity changes that were selective for a particular sequence of the three movements that the monkeys were prepared to perform. The sequence-selective activity ceased when the monkeys initiated the first movement. Second, we found interval-selective activity that appeared in the interval between one particular movement and the next. Third, we found neuronal activity representing the rank order of three movements arranged chronologically; that is, the activity differed selectively in the process of preparing the first, second, or third movements in individual trials. The interval-selective activity was more prevalent in the SMA, whereas the rank-order selective activity was more frequently recorded in the pre-SMA. These results suggest how neurons in the SMA and pre-SMA are involved in sequencing multiple movements over time.

[Thallium-201 single photon emission tomography of intracranial angiomas]

We herein describe thallium-201 single photon emission tomography (T1-201 SPECT) findings in three cases with intracranial angioma. One of the lesions which was associated with chronic encapsulated intracerebral hematoma showed moderate accumulation of T1-201, but, others demonstrated no accumulation. The usefulness and limitations of T1-201 SPECT in differential diagnosis of intracranial mass lesions are discussed.